Well, for transparent dashboard you might want to read these
http://www.wowinterface.com/forums/s...ad.php?t=23344
http://www.wowinterface.com/download...nvisiSkin.html
I'm not sure how relevant the file editing is anymore, since nUi has the /nui viewport command that disables the viewport and I guess the problem described in the faq is no longer relevant.
Since nUI is mostly mend as a all in one mod and easy to make it look how you want it the consensus on transparent dashboards doesn't really matter.
Unfortunately, nUI5 kinda lacks the easy way to adjust the gui. nUI6 should improve that tho. (meaning most "skins" still use the default layout and dont move anything around)